Punch press



April 18, 1944. s 2,346,719

PUNCH PRESS Filed Aug. 18, 1942 4 Sheets-She et 1 PIERCING J/G [VI/ENTOEZEO/V/IBD E. AJKE ZJW L. E. ASKE PUNCH PRESS April 18, 1944.

4 'Sheets-Shee 2 Filed Aug. 18, 1942 April 18, 1 944. s 2,346,719

PUNCH-PRESS Filed Aug. 18, 1942 4 Sheets-Sheet 3 ELECTRIC M/IGNE TIC 6372 63 STRIP/ EE PLATE ivy/M1702 LEON/JED E. AJKE A TTOENEYJ PatentedApr. 18, 1944 PUNCH PRESS Leonard E. Aske, Minneapolis, Minn, assignorto Dayton Rogers Manufacturing 00., Minneapolis, Minn, a corporationofMinnesota Application August 18, 19.42, Serial No. 455,251 22 Claims.(Cl. 164-102) This invention relates to new and useful improvements inpunch presses, generally, and more particularly to punch presses usedfor punching various sizes of holes in metal stampings.

Punch presses, as now commonly constructed,

have the punch suitably mounted on the bed plate of the press, and thedie is carried by the ram mounted over the bed plate. The blank orstamping to be pierced, is supported in what is commonly known to thetrade, as a piercing Jig, which consists of a flat metal plate havingthe proper size holes jig-bored therein. To this plate is secured apiece of sheet metal, usually produced from a piece of the blanked outpart of the metal strip from which the blanks have been blanked. Thispiece of blanked out metal i riveted to the jig-bored metal plate withthe opening therein accurately located with respect to the drilled holesin the Jig plate, and provides what is commonly known to the trade as a"nest." The contour of the opening in the blanked out metal strip isidentical to the contour of the blank to be pierced, whereby the blankmay readily be placed in the nest of the piercing jig, preparatory tobeing pierced.

In the operation of a conventional press in which the punch is mountedon the bed plate,

whereupon the ram is actuated and forces the die into piercingengagement with the blank, whereby the punch pierces the blank, as iswell known.

To accurately.position the piercing jig with respect to the punch, in aconventional press, often requires considerable time, as the operatorcannot see the end of the punch to guide it into the guide hole in thepiercing Jig. The operator must therefore guide the piercing Jig aroundon the tip of the punch until the latter enters the selected guide holein the Jig. Each time the blankhas been pierced by the punch, the jig isremoved from the punch, and the pierced blank knocked out of the nest. Anew blank is then placed in the nest, and the sanie v operationrepeated. This method is slow because the operator cannot, as a rule,initially place the piercing ill; on the punch whereby the punch willimmediately enter the selected guide hole in the Jig, and he musttherefore feel his way," or guide the iig plate around on the end of thepunch until it enters the selected guide hole in the Jig. Such slidingof the piercing jig on the end of the punch to accurately align it withthe punch and die, is also objectionable in that it has atendency todull the cutting edge of the-punch.

To expedite the operation. of piercing holes in blanks, I have foundthat by inverting the punch and die in the punch press, the operationofguiding the Jig plate onto the punch" usual ram of the press which, inthe present instance, is mounted for reciprocal movement in a guideprovided in the bed plate of the press. When th punch and die are thusinverted in the press frame, the piercing 118 must be correspondinglyinverted, whereby the guide holes therein are clearly visible to theoperator because they are then exposed to view on the top side 'of thepiercing 118. it being understood that the blank to be pierced is thensupported in the nest on the bottom side of the 118. By thus invertingthe piercing Jig, it will readily be seen that the operation of guidingthe piercing iig into accurate registry with the punch is greatlyfacilitated, as the selected guide hole in the piercing jig is clearlyvisible to the operator at all times, whereby he may quickly move theJig into alignment with the punch to properly position the blank withrespect to the punch and die.

An object of the present invention therefore is to provide a punch pressin which the ram carrying the die is mounted in the bed plate of thepress below the punch, and the punch is mounted in the upper portion ofthe press frame directly over the die, whereby the operator may readilyand quickly guide the piercing jig into accurate registry with the punchand die with a minimum of-eiiort and labor.

A further object of the invention resides in the provision of electricalmeans for holding the piercing Jig in fixed accurate relation withrespect to the punch, during the piercing operation, whereby each blankwill be accurately pierced.

A further object is to provide an electro-magnetic stripper plate havinga normally open control circuit provided with a pair of spacedcontacts'which are associated with the stripper plate and so related tothe punch that when the piercing jig is accurately guided onto thepunch, the piercing jig will bridge said contacts and close the controlcircuit, whereby the coils in the stripper plate are instantly energizedto thereby cause the stripper plate to momentarily become a magnet anddraw the piercing jig into firm contact therewith during the piercingoperation.

A further object is to provide a punch press provided with means forfixedly supporting a punch, and having a ram mounted for reciprocalmovement below the punch and carrying a die, and an electro-magneticstripper plate being mounted adjacent to the punch and having aconnection with a suitable cushioning means, whereby when the die ismoved into engagement with the blank byreciprocal movement of the ram,the piercing jig in which the blank is supported, may yield underpressure in such a manner that when the die moves out of engagement withthe punch, the stripper plate will strip the blank from the punch in theusual manner.

A further object is to provide a punch press comprising anelectro-magnetic stripper plate provided with a control circuit having apair of spaced contacts which preferably are mounted in the stripperplate and positioned to be engaged by the piercing jig, after thepiercing jig has been properly guided onto the lower end of the punch,whereupon the control circuit is temporarily closed and thereby rendersthe drive clutch operative to drive the ram and move the die intopiercing engagement with the punch.

A further object is to provide a press of the character disglosed,comprising an electro-magnetic stripper plate, a drive clutch, a controlcircuit for the stripper plate and drive clutch, and a circuit breakerfor opening the control circuit immediately following the blank-piercingoperation, whereby the crank shaft may come to rest at the end of eachblank-piercing cycle.

A further object is to provide a punch press comprising anelectro-magnetic stripper plate, an electrically controlled driveclutch, a suitable motor, and a safety device mounted adjacent to thepunch and operatively connected to a cutout switch interposed in themotor circuit, and also to a cutout switch provided in a control circuitfor the stripper plate and drive clutch, said safety device being soconstructed that when in normal inoperative position, the motor andcontrol circuits will be open, whereby the press cannot be operated,said safety device requiring that it be manually moved into operativeposition before the motor can be started and also to condition thecontrol circuit for operation, when a piercing jig is subsequentlyinterposed between the punch and the die in position to bridge a pair ofspaced contacts in the control circuit, whereby the ram may be operated'to move the die into piercing engagement with the blank.

A'further object is to provide an electric control means for punchpresses'which renders the press substantially automatic in operation,and whereby the usual operation of manually tripping a control lever, asis now common in the o eration of punch presses, is entirely eliminated,the starting of the press depending entirely upon the correctpositioning of the piercing jig in relation to the punch.

Other objects of the invention reside in the provision ofan-elect'ro-magnetic stripper plate having the dual function oftemporary holding a piercing jig during the blank-piercing operation,and which also serves to strip the blank from the punch, when the blankhas been pierced; in the unique construction of the clutch operatingmeans, which is operated by a solenoid coil having a normally opencircuit which is adapted to be closed by a suitable relay, when thecontrol circuit is closed by the piercing jig to thereby energize thestripper plate; in the provision of a simple and inexpensive controlmeans for a punch press whereby the entire operation of the press may besubstantially automatic, and is controlled entirely by the insertion ofa piercing jig blank in position with respect to the punch; in theprovision of a safety device comprising a movable member positionedadjacent to the punch and die and operatively connected to the motorcutout switch and to a suitable cutout switch in the control circuit,whereby when the safety device is in inoperative position, as when thepress is at rest, the motor cannot be started to operate the ram, saidsafety device being so constructed that it must be moved into operativeposition in front of the punch and die before the press can be startedto pierce the blank.

Other objects of the invention will appear from the followingdescription and accompanying drawings and will be pointed out intheannexed claims.

In the accompanying drawings there has been diclosed a structuredesigned to carry-out the various objects of the invention, but it is tobe understood that the invention is not confined to the exact featuresshown, as various changes may be made within the scope of the claimswhich follow.

In the drawings:

Figure 1 is a view of a. punch press with the invention embodiedtherein;

Figure 2 is an enlarged detail sectional view of the upper portion ofthe press frame, showing the electro-magnetic stripper plate and thecushion which operatively supports it;

Figure 3 is a view similar to Figure 2, but showing the ram movedupwardly to force the punch through the blank;

Figure 4 is a front view of Figure 2 with the upper portion of thestructure broken away, and

showing the safety device in operative position;

Figure 5 is an enlarged detail sectional view showing the piercing Jigpositioned against the stripper plate with the punch received in one ofthe guide openings thereof;

Figure 6 is a bottom view of the stripper plate, showing the spacedcontacts mounted therein;

Figure 7 is a sectional plan view substantially on the line 1--1 ofFigure 2;

Figure 8 is an enlarged detail sectional view on the line 8-8 of Figure7;

Figure 9 is a plan view of the piercing jig showing the guide holesprovided therein for accurately positioning theblank with respect to thepunch;

Figure 10 is a detail sectional plan view on the lines Ill-40 of Figures2 and 4;

Figure 11 is a perspective view of the bottom of the piercing jig,showing the nest provided therein for supporting the blank;

Figure 12 is a bottom view of the piercing jig. showing the means forfrictionally supporting the blank in the nest;

Figure 13 is a detail sectional view on the line l3-l3 of Figure 1,showing the clutch;

Figure 14 is a schematic wiring diagram showing the electric circuits ofthe apparatus; and

Figure 15 is a detail view of the upperportion of the stripper platecushion, showing the knockout pin for the punch.

In the selected embodiment of the invention herein disclosed, there isillustrated in Figure 1, for purposes of disclosure, a punch pressincluding a suitable supporting structure or frame, generally designatedby the numeral 2, comprising uprights 3 having a suitable bed plate 4secured thereto. A shaft 5 is rotatably mounted in suitable bearingsprovided on the uprights 3, and has a flywheel 6 mounted for relativerotation thereon. The flywheel is shown driven from a motor 1 thru aflexible drive 8.

A clutch, generally designated by the numeral 9, is provided on theshaft 5 for drivingly connecting the flywheel to the shaft. The clutch 9may be of any suitable construction applicable for the purpose, and inthe present instance is shown provided with a hub II which isnonrotatably secured to the shaft. A spring-actuated bolt I2 is slidablymounted in the hub I and has its inner end arranged to be received inone of a series of sockets l3, provided in the adjacent face of the hubof the flywheel, thereby to drivingly connect together the hub I andflywheel 6 for rotation as a unit with the shaft 5, as will beunderstood by reference to Figures 1 and 13. A suitable spring, notshown, is provided for constantly urging the bolt I into drivingengagement with the flywheel 6.

A clutch operating arm I4 is pivoted at l5 to a portion of the frame 2,and has one end adapted to engage a pin or head I6 provided on the boltl2, thereby to pull the bolt out of driving engagement with the flywheeland interrupt rotation of the shaft. A spring l1 normally holds theclutch control arm M in the position shown in full lines in Figure 13,whereby the bolt I2 is held out of driving engagement with the flywheel.The clutch arm M is adapted to be moved out of engagement with the drivebolt |2 by a suitable solenoid l3, having a connection with the clutcharm l4 through a suitable member l9, shown in Figures 1, 13 and 14.

A ram 2| is mounted in a suitable guide hearing 22 in the lower portion23 of the punch press frame, proper, generally designated by the numeral24. The frame 24 is secured to the bed plate 4, although if desired, itmay be made integral therewith. The ram 2| is driven from the shaft 5 bya pitman 25 shown having a ball-andsocket connection 26 with the lowerend of the ram. The lower end of the pitman is engaged with an eccentric21 secured to the shaft 5. The

eccentric 21 isso related to the clutch 9, that when the shaft comes torest at the end of each blank-piercing cycle, the ram will be at thebottom of its stroke, as shown in Figures 2 and 14.

A suitable die, generally designated by the numeral 26, is removablysupported on the upper end of the ram 2| by a suitable member 29 shownsupported in a socket 30 provided in the end of the ram. The member 29is retained in the socket 30 by a clamping ring 3| secured to the ram byscrews 32. A suitable backing plate 33 is prefer. ably provided in thebottom of the socket 36, to provide an abutment for the lower end of thedie 26, as clearly illustrated in Figure 2. The ram 2| is shown providedwith a suitable passage 26 which isaligned with a passage 36 in theabutment plate 33. whereby the punchings removed from the blank may passtherethru into a suitable receiving means, not shown in the drawings.

An important feature of the present invention resides in mounting thepunch, generally designated by the numeral 34, in the upper portion ofthe frame 24 of the punch press, over the die 28, as best shown inFigurez, whereby the punch is clearly visible to the operator at alltimes, when inserting a piercing jig, generally designated by thenumeral 35, into accurate alignment with the punch and die.

To support the punch over the die 28, as shown in Figure 2, the frame 24isshown provided with forwardly extending spaced side members or flanges36 between which a punch holding block 31 is mounted, as shown inFigures 4 and 10. The

block 31 has opposed flanges 31' seated against the lower edges of theflanges 36 and secured thereto by suitable screws 31". .The block 31 ishorizontally adjustable by manipulation of suitable adjusting screws 38and 39, as best shown in Figure 10. The screws 33 are received insuitable apertures provided in the side frame members 36, and have theirinner terminals received in threaded engagement with the block 31. Theadjusting screws 39 are received in threaded engagement with a wall 4|of the press frame, and have their inner ends adapted to engage theblock 31. By thus supporting the block 31 in the frame 24, it mayreadily be adjusted in a horizontal plane within certain limits toaxially align the punch with the die 28.

The block 31 has a counter bore 42 adapted to receive the usual punchholding cage, generally designated by the number 43, which, as bestshown in Figure 2, comprises upper and lower members 44 and 45, securedtogetherby suitable bolts or screws indicated at 46. A flanged element41 is mounted within the lower member 46 of the punch holding cage, andhas a socket 46 therein for supporting the punch, as clearly shown. Aspring-actuated retaining ball, generally designated by the numeral 46',is mounted in the wall of the socket 40, and is adapted to engage arecess in the shank of the punch 34, in the usual manner, thereby toretain the punch in the socket.

The punch holding cage 43 is mounted for vertical adjustment within thecounter bore 42 to properly position it with respect to the die. To thusvertically adjust the cage 43, the upper washer-like member 44 thereofis shown supported on the lower flanged head 49 of a vertically disposedstem 5| having an enlarged threaded portion 52 adjacent its head 49received in threaded engagement with the block 31, whereby rotation ofthe stem 5| will vertically translate the stem in the block 31, aswillreadily be understood. A sleeve 53 is mounted for rota- 5| between theenlarged of the sleeve 53 is received in threaded engagement with theupper portion 56 of the block 31.

An enlarged washer 66-15 mounted on the sleeve 63 and is seated on theupper end of the portion 66 of the block 41. A similar washer 51 isengaged with the flanged head 58 of the sleeve 63, and a suitablecushion element 59 is moimted on the sleeve 63 between the washers 56and 61, as clearly illustrated in Figures 2 and 3. The cushion element59 may be constructed of rubber, or any other material suitable for thepurpose.

A suitable handwheel 6| is secured to the upper end of the stem 5| andprovides means whereby the stem may be conveniently rotated tovertically adjust the punch with respecttothe die 26. A

' punch from the socket 136, when it is necessary to substituteone punchfor another. Such means is shown comprising a knock-out pin 56 slidablymounted in a bore in the tubular member i, and having its lower terminalarranged to engage the upper end of the shank of the punch, as'clearly Iillustrated in Figure 2. The upper end of the knock-out pin 50 isprovided'with a knob 66 between which and the wheel 60 a suitable spring16 is mounted. The spring 76 normally retains the knock-out pin in itsinoperative position,

shown in Figure 2. I

To remove the punch by manipulation of the I knock-out pin 50, theoperator will insert a small pin or wire into an aperture 88 provided inthe flanged member 41, in alignment with the retaining ball 40', andmove said ball partially out of the,

ascetic piercing jig 36 into accurate alignment with the punch, as willsubsequently be described.

Another feature of the present invention resides in the electrificationof the stripper plate 65;, whereby, in addition to serving as a stripperplate for removing the pierced blanks from the punch, the stripper platemay also function as a means for firmly holding the piercing jig inposition with respect to the punch during the blank-piercing operation.To thus electrify the stripper plate, a

, a series of coils or windings 52 are mounted in annular grooves '13 inthe body of the stripper plate, as clearly illustrated in Figure 4. Thecoils 12 are connected in series with a control circuit,-

generally designated bythe numeral 18, in Figure 14. A pair of spacedcontacts I5are provided in the control circuit I4, and are preferablycated in'the stripper plate as adjacent to the punch 34,-as shown inFigure 6. The ends of the contacts 15 protrude downwardly a relativelyshort distance below the lower surface of the recess in the shank of thepunch. The knock-out.

pin may then be operated to quickly eject the punch from the'socket All,to permit another punch to besubstituted therefor.

From the foregoing, it will be noted that the stripper plate 63, asshown in Figures 2 and 8,

whereby they may readily be bridged by the stripper plate 63, when thepiercing die is moved upwardly into engagement with the lower face ofthe stripper plate, as shown in Figure 5. The lower terminal of thepunch 2 projects below the bottom surface of the stripper plate 63 arelatively greater distance than the contacts 15, as shown in Figure 4,whereby the mntacts 15 cannot be bridged to close the control circuituntil meterwrench or other suitable device may be applied thereto forrotating the sleeve.

Another important feature of the present invention resides in the novelconstruction of the means for successively stripping the blanks from thepunch, following each piercing operation. To thus strip or remove eachblank from. the end of the punch, a stripper plate, generally designatedby the numeral.63, is removably secured to the lower ends of a pluralityof rods 64, having their upper ends received in threaded engagement withthe lower plate or washer 56 of the cushion 59. It is to be understoodthat the plate or washer 56 is adapted for relative sliding movementupon the sleeve 53 thereby to permit compression of the cushion 59, whenthe stripper plate 63 is thrust upwardly as a result of the ram forcingthe piercing die into engagement therewith, during the blank-piercingoperation. The rods 66 are slidable in the block 31, as will beunderstood. The stripper plate 63 is removably secured to the' lowerterminals of the rods 64 by suitable lock screws 65 having their innerends adapted to be received in annular grooves 66 provided in the rods66, as will be clearly understood by reference to Figure 8. A suitablelock spring 6? is provided on each screw 65 to prevent the screws 65from accidentally working loose.

As best shown in Figures 2, 6 and 7, the periphcry of the stripper plate63 has a re-entrant notch Ell therein which is aligned with a cutoutportion 69 in the block Bl, whereby the operator has, a clear line ofvision, as indicated by the arrow M in Figure 2. In other words, bynotching the stripper plate 63 and block 37, as above-described, theentire lower end portion of the punch is always visible to the operatorstationed in front of the machine, whereby he may readily guide theminal of the punch 34 has been accurately aligned with'the work as byentering one of the jig-bored holes in the jig plate, as shown inFigures 3 and 5.

The control circuit 14 is shown comprising a wire 16 having one endconnected to one of the coils. 12 in the stripper plate, as shown at 11in Figure 14. The opposite end of the wire 16 may be connected to thefixed contact 18 of a cutout switch 19. other side of the switch 19 toone side of a battery 8!, whose opposite side has a wire 82 connectingit to one side of a coil 83 of a suitable relay, enerall designated bythe numeral 84. A wire 86 connects the opposite end of the relay coil 83to one end of a pivoted arm 86 of a. circuit breaker 90. The arm 86 isadapted to be actuated by a suitable cam 81 secured to the shaft 5 ofthe press. A contact 88 is secured to the arm 86 adapted to electricallyengage a contact 89 provided on a relatively fixed member 8| of therelay 84. A wire 82 electrically connects the member 9| to one end 83 ofone of the magnetic coils 12 of the stripper plate 63. It will thus beseen that a complete circuit is provided through the battery 8!, whenthe arm 86 is electrically engaged with the contact 89, and the spacedcontacts 15 of the stripper plate are bridged by the piercing jig 35.

Such closing of the control circuit 14 will have no effect upon thepress, unless the drive clutch 9 is operated torelease the drive pin l2and permit it to engage the flywheel 6, whereupon the punch press willgo through one cycle of operation.

To automatically actuate the drive clutch 6, when the control circuit isclosed as a, result of the contacts 15 being bridged by the piercingjig, the solenoid coil l8, shown in Figure 14, is electrically connectedin the control circuit by a wire as connecting one end thereof to thewire 86, leading to one side of the storage battery 8|. The other sideof the solenoid; coil M has a wire 96 conmeeting it to a fixed contact96, having a complemental contact 9'! electricall connected to the Awire 86 electrically connects the I Y battery 8! through a wire 88. Acontact member 88 is shown carried by the armature IOI of the relay coil83, and is adapted to be moved into electrical engagement with thecontacts 96 and 81 to close the circuit between the wires 95 and 98,when the relay coil 83 is energized. The motor I is connected to asuitablesource of current supply through a supply circuit I02, having asuitable cutout switch I03 interposed therein.

Another feature of the invention resides in the provision of a safetydevice which is so positioned as to prevent an operator fromaccidentally inserting his hand between the punch and die in theoperation of inserting the piercing jig therebetween.

As shown in Figures 2, 3, 4 and 14, the safety device above referred tois shown comprising upright side plates E04, which may be secured to theopposed sides of the lower portion of the frame 24 of the punch press,as clearly illustrated in Figures 3 and 4. The upper edges I of the sideplate 904 are spaced above the upper terminal of the die 28, andcooperate to provide a support for the piercing jig 35, as clearlyillustrated in Figures 2 and 4.

The piercing jig, as best illustrated in Figures ll and 12, comprises afiat metallic plate I08 having jig-bored holes l0! and I08 providedtherein corresponding to the size and number of holes to be pierced inthe blank. These holes are accurately jig-bored in the metallic plateI06, and a nest is then provided on one side of the piercing jig forreceiving the blank to be pierced, generally designated by the numeral809, in Figures 2, 3, 4 and 12. The nest is usually formed by securingto the plate I06 a portion ill of the metal strip from which one of theblanks l09 has been blanked, whereby the contour of the opening H2 inthe metal strip I I I will, of course, be identical to the configurationof the blank I09. A suitable friction element H3, preferably of rubber,although it may be of any other suitable material applicable for thepurpose, is provided in a wall of the nest I I2 for frictionallysupporting the blank E09 therein, while positioning the pierclng jig inalignment with the punch 34.

The friction element H3 is so designed and constructed as to securelyhold the blank in position in the nest I I2 while supporting thepiercing jig in an inverted position, that is, with the blank on thebottom side of the piercing jig, in the operation of guidin the selectedhole therein into alignment with the punch 34.

To prevent accidentaI or premature starting of the press, before thepiercin jig has been properly positioned with respect to the punch, thesafety device hereinbefore referred to, is provided with a movable guardmember or bar H4 which,

when in operation, is positioned in front of the die between the sideplates or walls I04 of the safety device. The member H4 is supported bydownwardly extending arms H5, pivoted to the frame of the press bsuitable pivots H0, as will be understood by reference to Figures 2, 3and 4. A spring-actuated bolt H1 is mounted in one or both of the arms II5 01 the safety bar H4, and serves to lock the bar H4 in its operativeupright position, shown in Figures 2, 3 and 4. When the spring bolt 1 ispulled outwardly, the bar H4 may be swung forwardly to the dotted lineposition shown in Figure 3.

When the safety bar I I4 is in its operative position, its upper edge H8will be disposed in the plane of the upper edges I05 of the side platesI04, whereby the bar H4 will cooperate with said side plates I04 toprovide a substantial support for the piercing jig 35, when it isinitially inserted between the punch and die in the operation ofaligning one of the holes therein with the punch 34, as will readily beunderstood by reference to Figure 2 and 4.

Another feature of the invention resides in so interconnecting thepivoted safety bar H4 with the control circuit I4 and the motor supp ycir cuit I 02 that when the safety bar is in its inoperative positionshown in dotted lines in Figure 3, and full lines in Figure 14, thesupply of current to the control circuit l4 and the motor l is cut off,whereby the punch press cannot under any conditions be set into motion,so long as the safety bar is in its inoperative position.

To thus interrupt the supply of current to the control circuit I4 andmotor 7!, when the safety bar H4 is in its inoperative position, eachsupporting arm N5 of the safety bar H4 is shown provided with a switchactuating end portion 6 l9, one adapted to open the motor cutout switchI03, and the other adapted to open the cutout switch it of the controlcircuit 74. In the wiring diagram shown in Figure it, I have shown thecutout switches I9 and 603 as being actuated by a single switch memberHi. It is to be understood, however, that the two cutout switches arepreferably, but not necessarily mounted independently of one another, asshown in Figure 4, one on each side of the press frame, and that theparts are merely diagrammatically illustrated in Figure 1d. The sidearms H5 of the safety bar He operate in synchronism, whereby theswitches I9 and I03 are always opened simultaneously and closedsimultaneously, even though they are mounted independently of oneanother, as shown in Figure 4. In some instances, however, it may befound more desirable to mount the switches I8 and I08 in a singlecasing, whereby they may be simultaneously operated by a single switchoperating mem- 7 her I2I, as now shown in Figure 14.

In the operatipn of the novel punch press herein disclosed, the blank tobe pierced isfitted into the nest I I2 in the piercing jig 85, as willreadily be understood by reference to Figures 11 and 12. The piercingjig is then positioned upon the upper edges of the side plates I04 andsafety bar H4, as clearly illustrated in Figures 2 and 4, with the blankfacing downwardly. The operator aligns the selected aperture I0'I or I08in the piercing jig with the punch, and lifts the piercing jig slightlyupwardly until the lower end of the punch enters the selected hole inthe jig. When the punch enters the selected hole in the jig, the jigwill engage and bridge the contacts I5 of the control circuit I4,whereupon said cir-' cult is closed through the battery 82 with theresult that the electro-magnetic stripper plate 63 is instantlyenergized and thereby magnetically draws the piercing jig into firmcontact therewith, as shown, for example, in Figure 5.

Simultaneously as the stripper plate 63 is energized, the coil- 83 ofthe relay 84 is energized to cause the member 98 to bridge the gapbetween the contacts 98 and 8'! and thereby close the circult to thesolenoid coil I8 of the drive clutch9. Such energization of the solenoidI8 will cause the clutch bar I4 to be pulled out of engagement with theoffset pin or head IQ of the clutch drive bolt I2, thereby permittingsaid pin to drivingly engage the flywheel 8, whereby the shaft isrotatedto operate the ram and move the die into blank-piercing engagement withthe punch, as clearly illustrated in Figure 3.

When the punch press is in operation over a period of time, the safetybar H4 is usually left in its operative position, shown in full lines inFigures 2 and 3, whereby the cutout switches '89 and 503 are closed.Under such conditions, the motor I will rotate continuously with theresult that the flywheel 6 will also rotate continuously, so long as thesafety bar lid is in operative or switch closing position.

Rotation of the shaft 5, however, is temporarily interrupted after eachcomplete revolution thereof as a result of the circuit breaker 90, whichis arranged to open or break the control circuit during each half cycleof operation, whereby the solenoid coil 88 of the clutch isde-energized, and, at the same time, the coil 83 of the relay 84 isdeenergized. De-energization of the solenoid coil it will permit thespring ll of the clutch arm M to pull said arm upwardly into the path ofthe pin or head 55 of the driving bolt 82, whereby the drivingconnection between the shaft and the flywheel is interrupted until theclutch arm is is again actuated to permit the drive bolt 92 to enter oneof the sockets B3 in the flywheel.

The operation of the circuit breaker 959 is so timed with respect to thetraveling movement of the ram that immediately following the piercing ofthe blank, as shown in Figure 3, the cam til will actuate the circuitbreaker arm at and thereby move its contact 88 out of electrical contactwith the fixed contact 89, whereupon the entire apparatus is renderedinoperative, with the exception of the motor l and flywheel S. The relay8% serves to interrupt the supply of current to the solenoid coil 9 8from the battery fit, when the ram comes to rest.

At the termination of each cycle of operation, and when the ram ispositioned as shown in Figure 14:, the circuit breaker is returned toits closed position, whereby the control circuit W is conditioned foroperation the moment the spaced contacts "E5 thereof are bridged by thepiercing jig 35, when the latter is moved into engagement with thepunch, 'as shown in Figure 5.

From the foregoing it will thus be seen that the entire operation of thepunch press is automatically controlled by the insertion of the piercingjig into position between the unch and die. The operation of accuratelypositioning the piercing die with respect to the punch has also beengreatly facilitated by the inversion of the die and punch, whereby thepiercing jig may be inverted, as shown in Figures 2, 3 and 4, so thatthe operator may at all times clearly view the lower end of the punch toguide it into the selected guide opening in the piercing jig. Theelectromagnetic stripper plate also greatly facilitates the operation ofpiercing the'blanks in that it practically becomes impossible for thepress to be started until the piercing jig, with the blank supportedtherein, is accurately and securely supported against the bottom face ofthe, stripper plate t8.

By the provision of the knock-out pin 50, the punch 36 may be quicklyremoved from its socket fill to permit another punch to be substitutedtherefor, without removing the electro-magnetic stripper plate from itssupporting means. There is ample room in the re-entra-nt notch in thestripper plate for the operator to readily insert a pin into theaperture 80' in the member 41 to render the retaining ball 40'ineffective to secure the shank of the punch in the socket 40, wherebythe knock-out pin 50 may radily be operated to eject the punch, when theretaining ball 40 is thus moved into inoperative position.

The novel punch press herein disclosed has made it possible to greatlyincrease the capacity of such punch presses, with less fatigue to theoperator. By mounting the flywheel and all of the operating mechanism ofthe press below the bed plate 3, the entire press may be made verycompact, whereby several such presses may be arranged side by side in arow, or in a semi-circular manner, whereby one operator may operateseveral machines. This is particularly advantageous when the blank is tohave several different size holes punched therein. For example, if ablank is to have three different size holes punched therein, an operatorstationed in operative position with relation to three or more machinesarranged in close proximity, as above stated, may punch all of the holesin the blank without removing the blank from the piercing jig, by simplymoving the jig from one press to the next, each press being providedwith a different size punch and die, corresponding to the differentsizes of holes to be pierced in the blank.

Thus by grouping a plurality of punch presses as above stated, whereby asingle operator may readily and conveniently operate more than onemachine, the operation of punching several different size holes in agiven blank may be greatly expedited, because the operation of removingthe blank from the jig after each different size hole is' punchedtherein, may be entirely eliminated, and all of the different size holesmay be punched with one setting of the blank in the jig. For someclasses of work it may be found more desirable to pass the jig with theblank supported therein from one operator to another, each operating adifierent press, and the various presses be equipped with different sizepunches, whereby a blank which is to have several different size holespunched therein, may readily be pierced without removing it from thejig, by thus passing the jig from one operator to another.

In the drawings I have shown the Control circuit i as receiving itssupply of current from a storage battery, but, if desired, it may besupplied from a transformer connected directly to the usual power supplyline, without departing from the scope Of the invention. The supplycircuit is preferably a low voltage circuit.

It will be apparent to those skilled in the art that I have accomplishedat least the principal objects of my invention, and it will also beapparent to those skilled in the art that the embodiments hereindescribed may be variously changed and modified, without departing fromthe spirit of the invention, and that the invention is capable of usesand has advantages not herein specifically described; hence it will beappreciated that the herein disclosed embodiments are illustrative only,and that my invention is not limited thereto.

I claim as my invention:

1. A punch press comprising a frame including a bed plate having a guidetherein, a ram mounted in the guide, operating means for the ram, a diesecured to the upper end of the ram, a punch mounted in the frame overthe die and operatively aligned therewith and normally spaced from thedie, and means for supporting the work between the die and punch andthereafter stripping it from the punch.

2. A punch press comprising a frame including a bed plate having a guidetherein, a ram mounted for vertical movement in said guide,

ascetic operating means for the ram, 'a die removably secured to theupper end of the ram, a punch mounted in the frame over the die inoperative relation thereto and normally spaced from the die to permitinsertion of a blank-supporting jig punch to accurately align the blankwith the punch beforethe piercing operation is started.

3. A punch press comprising a frame including a bed plate having avertical guide therein, a ram mounted in the guide, crank means in thelower portion of the frame for operating the ram, a punch removablysupported in the frame above the die in alignment therewith, a yieldablestripper plate supported in the upper portion of the frame forstrippingthe work from the punch, when the punch has pierced the work, and meanswhereby the stripper plate may hold the work independently of theoperator during the piercing operation.

4. A punch press comprising a frame including a bed plate having avertical guide therein, a ram mounted for reciprocal movement in theguide, means in the lower portion of the frame for operating the ram, adie removably supported on the upper end of the ram, a punch mounted inthe frame over the die in align- -ment therewith and normally spacedfrom the die to permit insertion of a piercing jig with a blanksupported therein between the die and punch, a stripper plate mountedin'the upper portion of the frame, and cushion means for yieldablyresisting relative movement of the stripper plate, during the piercingoperation, and whereby the blank is stripped from the punch,. when thepunch has pierced the blank.

5. A punch press comprising a frame including a bed plate having a guidetherein, a ram mounted in the guide, operating means for the ram, a diesecured'to the upper end of the ram, a punch mounted in the frame overthe die and operatively aligned therewith and normally spaced from thedie, a stripper plate mounted adjacent to the punch with its bottomsurface spaced upwardly from the lower terminal of the punch, and meansfor supporting a piercing jig between the die and punch to facilitateguiding the piercing jig into. alignment with the punch.

6. A punch press comprisinga frame including a bed plate having avertical guide therein, a ram mounted for reciprocal movement in theguide, operating means for the ram, a die removably secured to the upperend of the ram, a punch fixed in theframe over the die and alignedtherewith and normally spaced from the die to permit a piercing jig witha blank supported therein, to be inserted between the die ,and punch,and a stripper plate associated with the punch for stripping the piercedblank therefrom, said stripper plate having a re-entrant notch in itsperiphery whereby the punch is clearly visible to the operator whenguiding the piercing jig onto the punch.

7. A punch press comprising a frame having a punch mounted in the upperportion thereof, a guide in the lower portion of the frame, a rammounted in the guide, driving means for the ram, a die carried by theupper end of the ram,

and a stripper plate mounted adjacent to the punch with its lower facespaced upwardly from the lower terminal ofthe punch, said stripper platehaving a re-entrant notch therein whereby the punch is exposed to theoperator to facilitate guiding a piercing jig onto the punch in theoperation of placing the blank in position between the punch and die.

8. A punch press comprising a frame having a punch mounted in the upperportion thereof, a guide in the lower portion of the frame, a rammounted in said guide, driving means for the ram, a die carried by theupper end of the ram. a stripper plate mounted adjacent to the punchwith its lower face spaced upwardly from the lower terminal of thepunch, said stripper plate having a re-entrant notch therein whereby thepunch is exposed to the operator to facilitate guiding a piercing jigonto the punch in the operation of placing the blank in position betweenthe punch and die, and means carried by the stripper plate and madeoperable by engagement with the piercing jig to cause the ram drivingmeans to operate and actuate the punch.

9. A punch press comprising a frame having a guide therein, a rammounted in the guide, operating means for the ram, an electro-magnetiestripper plate, a die secured to the ram, a punch mounted in the framein alignment with the die and passing through an opening in the stripperplate and having its lower end spaced downwardly from the bottom face ofthe stripper plate, a jig for supporting the blank to be pierced, saidjig having a guide opening therein adapted to receive the end of thepunch to accurately align the blank with the punch and die, and meansmade operable by engagement with the jig, after the jig has been guidedonto the punch, thereby to cause energization of the stripper platewhereby the stripper plate will accurately hold the jig and blank duringthe piercing operation,

10. A punch pres comprising a frame having a guide therein, a rammounted in the guide, operating mean-,; for the ram, a die secured tothe ram, a punch mounted in the frame in alignment with the die, anelectro-magnetic work-holding device and control means for said devicepositioned to be engaged by the work when the work is inserted betweenthe die and punch, thereby to render said device operable to hold thework in operative relation to the punch during the. piercing operation.

11. A punch press comprising a frame, complementary blank piercingelements "mounted in said frame, one of said elements being fixed andthe other movable, operating means for the movable element, a jig forsupporting a blank and control means operatively associated with saidoperating means and comprising a pair of spaced contacts, said contactsbeing adapted to I prising a pair of spaced contacts, said circuit beingoperatively associated with the driving means and said contacts beinglocated adjacent to one of the blank piercing elements, whereby when apiercing jig with a blank supported therein is in serted between thepiercing elements and bridges the gap between said contacts, the circuitis closed to the driving means, whereby the movable piercing element isoperated to pierce the blank.

.13. A punch press comprising a frame, a punch supported in said frameand restrained against axial movement, a die mounted for movementtowards and away from the punch, means for driving the die, anelectro-magnetic stripper plate positioned adjacent to the punch, acontrol circuit electrically connected to the windings'of the jig isinserted between the punch and the die, I

whereby the control circuit is closed and causes the stripper platetobecome energized to hold the piercing jig in position with respect tothe punch, I

during the piercing operation.

' 14. A punch press comprising a frame having a guide therein, a ram'mounted in the guide, operating means for the ram, a die secured to Ithe ram, a punch mounted in the frame in alignment with the die, astripper plate mounted ad;-

jacent to the punch for stripping the blank from I the punch followingthe piercing operation, a

magnetic coil in the stripper 'plate,'a normally open control circuitelectrically connected to said coil and operatively associated withthe'ram driving means, and spaced contacts in the control circuitadapted to be bridged by a piercing jig in.- serted between the die andpunch, whereby the circuit is closed to said coil and to the ram drivring means, energization of said coil causing the stripper plate totemporarily hold the piercing jig in accurate position withrespect tothe punch.

during operation of the punch to pierce the blank supported in the jig.

15. A punch press comprising a frame having a punch removably supportedin the upper portion thereof, a guide in the lower portion of the frame,a ram mounted in said guide, a die removably secured to the upper end ofthe ram, means for operating the ram, a stripper plate carried on theupper portion of the frame and having its lower face spaced upwardlyfrom the lower terminal of the punch whereby an oper ator may readilyand conveniently guide a piercing jig onto the lower end of the punch toaccurately position the blank with respect to the punch and die,cushioning means operatively connected to the stripper plate andyieldably resisting movement thereof, control means for the ram drivingmeans, said control means being adapted to be engaged by the piercingjig, when the latter is moved into engagement with the stripper plate,whereby the driving means is rendered operative to actuate the die.

16. A punch press comprising a frame, means at the upper portion of theframe for removably supporting a punch, a ram mounted for reciprocalmovement below the punch, a die carried by the ram and aligned with thepunch, an electric motor, clutch means for drivinglyconnecting the ramto the motor, an electro-magnetic stripper plate having its lower facespaced upwardly from the lower terminal of the punch to facilitateguiding a piercing jig onto the lower end of the punch to align theblank with the punch, a normally open control circuit for the stripperplate become energized to firmly hold the jig in alignment with thepunch, energization of the control circuit simultaneously rendering theclutch means operative to drive the ram.

17. A punch press comprising: a frame, means at the upper portion of theframe for removably supporting a punch, a ram mounted for reciprocalmovement below the punch, a die carried by the ram and aligned with thepunch, an electric motor, clutch means for drivingly connecting the ramto the motor, an electro-magnetic stripper plate having its lower facespaced upwardly from the lower terminal of the punch whereby an operatormay readily and conveniently guide a piercing jig onto the lower end ofthe punch to align the blank with the punch, a normally open controlcircuit for the'stripper plate connected to a source of power, a pair ofspaced contacts in the control circuit positioned to be engaged by thepiercing jig, when the jig is moved into alignment with the punch,whereby the jig will bridge said contacts and thereby close the controlcircuit and cause the stripper plate to,

operation, energization of the control circuit simultaneously renderingthe clutch means opera- 7 tive to drive the ram, and means for renderingiii the clutch means inoperative, immediately following theblank-piercing operation.

18. A punch press comprising a ram having a punch mounted in the upperportion thereof, a guide in the lower portion of the frame, a ram Imounted for reciprocal movement in said guide,

a die carried by the ram, a motor foroperating the ram, an electricsupply circuit for said motor, an electro-magnetic stripper plate havingits lower face spaced upwardly from the lower end of the punch andhaving a re-entrant notch in its periphery whereby an operator mayconveniently and quickly guide a piercing jig onto the punch toaccurately align the blank with the punch and die, an electric'controlcircuit for the stripper plate and clutch means, and a normally operablesafety device so associated with the motor circuit and the controlcircuit that it must be moved into operative position by the operator,before said circuits can be closed to start the press.

19. A punch press comprising a ram having a punch fixedly mountedtherein, a guide in the frame aligned with the punch, a ram mounted forreciprocal movement in said guide, a die carried by the ram, a motorhaving a supply circuit provided with a cutout switch, a clutch fordrivingly connecting the motor to the ram, an electro-magnetic stripperplate having a re-entrant notch in its periphery whereby an opera- I tormay conveniently guide a piercing jig onto the punch to accurately alignthe blank with the punch and die, an electric control circuit for theclutch and stripper plate, a cutout switch in the control circuit, and asafety device comprising a pivoted member adapted to be positioned toprevent an operator from inserting a hand between the punch and die,when inserting the piercing jig therebetween, said pivoted member havingoperative connections with the motor circuit cutout switch and theswitch in the control circuit, whereby when said member is ininoperative position, the motor cannot be started to drive the ram.

20. A punch press comprising a frame, means in said frame for removablysupporting a punch.

a ram mounted for reciprocal movement in the frame, a die carried by theram and aligned with the punch, a motor for driving the ram, an electricsupply circuit for the motor comprising a cutout switch, clutch mtansfor drivingly connecting the motor to the ram, an'electro-magneticstripper plate, a normally open control cir-s cuit for the stripperplate connected to a source of power independent of the motor supplycirmally spaced from the die to-permit' insertion of the work betweenthe die and punch, and a knockout pin slidably mounted over the punchand arranged to be manually actuated to quickly remove the punch fromits supporting means, to permit another punch to be substitutedtherefor.

22. A punch press comprising a frame include ing a bed plate having aguide therein, a ram mounted in the guide operating means for the cuit,spaced contacts in the control circuit 10 ram, a cushion device mountedin the upper poradapted to be bridged by a piercing jig, subsequent-tothe punch entering one of the guide ergize the stripper plate and torender the clutch 3 means operative to drive the ram, a circuit breakerin the control circuit for temporarily opening said circuit immediatelyfollowing the blank-piercing operation, and a manually option of theframe and carrying a stripper plate, a tubular stem axially mounted inthe cushion device and having a punch-holder cage secured to its lowerend, said cage having a socket there- 5 in for receiving the shank of apunch, a springactuated ball mounted in a wall of said socket andengageable with a recess in the shank of the punch, thereby to securethe punch in said socket, means whereby said spring-actuated ball erablesafety device operatively connected to the 20 may be moved out ofengagement with the shank motor cutout switch in such fashion that saidsafety device must be moved into operative position by the operator,before the motor can be started to drive the clutch means.

of the punch, and a knock-out pin mounted in said tubular stem andhaving its lower end arranged to engage the end of the punch, and theupper end of the knock-out pin projecting-above 21. A punch presscomprising a frame includthe end of said stem whereby. the knock-out pinthe die in operative relation thereto and normay be convenientlyactuated to eject the punch from the socket, when the spring-actuatedretaining ball is in inoperative position.

LEONARD E. ASKE.

